Polymeric reaction product of polyalkyl substituted diisocyano compounds and polyhydrxy compound



United States Patent POLYMERIC REACTION PRODUCT OF POLYAL- KYL SUBSTITUTED DIISOCYANO COMPOUNDS AND POLYHYDROXY COMPOUND Lloyd C. Fetterly, El Cerrito, David O. Collamer, Orinda, and Curtis W. Smith, Berkeley, Calif., assignors to Shell Oil Company, a corporation of Delaware No Drawing. Filed Sept. 14, 1954, Ser. No. 456,078

11 Claims. (Cl. 260-75) This invention relates to a new class of diisocyanoand diisothiocyano-substituted aromatic compounds. More specifically, the invention relates to novel polysubstituted compounds of this type having especially advantageous properties and to the utilization of these new compounds.

The invention provides new and useful compounds which can be described as compounds having an aromatic ring system to which two, and only two, substituents of the group consisting of the isocyano and isothiocyano radicals are directly attached and having both positions ortho to said functional groups occupied by organic radicals. Due to this characteristic structural arrangement of the groups attached to the benzene ring, the novel diisocyanates, diisothiocyanates and isocyanoisothiocyanates have unexpected beneficial properties which make them particularly adapted for important commercial applications.

Organic polyisocyanates and polyisothiocyanates are known to be useful in the preparation of polymeric materials due to their ability to react with hydroxy, carboxyl, amine and like groups containing active hydrogen atoms. The use of these compounds as curing or vulcanizing agents for a variety of different types of polymers is described, for example, in U.S. Patent 2,3&1,06'3. In Industrial and Engineering Chemistry, vol. 46, pages 1498-1507 (.1954), other polymers from diisocyanates and polyols are described. It is pointed out in US. Patent 2,625,535 that careful control is essential in order to obtain products of this type having advantageous physical properties. One thing which contributes to the difficulty in obtaining products of the most desirable properties in such reactions is the tendency toward excessive cross-linking between polymer molecules which has been found to occur with the reactants heretofore employed. It is on this account that it has been found essential to use compounds with not more than two reactive isocyano or isothiocyano groups in the molecule for the preparation of polymers having desirable rubber-like properties. Even when using this type of compound, difiiculties have been encountered due to the ease with which the initial reaction product can undergo further reaction with the organic diisocyanates and diisothiocyanates previously available. Thus, for example, when reacting a diisocyanate with a hydroxy, carboxyl, or amino group, the respective products will contain urethane (all) (iii) amide and substituted urea 3,089,862 Patented May 14, 1963 Ice groups contain active hydrogen atoms which readily react with another molecule of the diisocyanate or diisotbiocy-anate. This can lead to excessive cross-linking which often makes the product difiicult to process or otherwise gives it less desirable properties. The compounds of the present invention, being less subject to such undesirable further reaction under these circumstances, facilitate production of polymeric products of improved properties.

The new compounds of the invention can be divided into subclasses according to the relative positions of the two isocyano and/or isothiocyano groups in the molecule. These groups can be on the same or different aromatic rings which can be single benzene rings or fused rings. The compounds which have been found to be most advantageous for the production of linear polymers are those having the two -'N=C=X groups (X being oxygen or sulfur) attached to non-adjacent ring carbon atoms. While those in which the --N=C=X groups are in ortho position to each other have other useful properties which make them a valuable part of the invention, they are much less useful as polymer linking agents or the like than the new compounds which have these groups further removed from each other. Especially preferred compounds of the latter type are those having the two N=C=X groups linked to the same benzene ring in meta or para positions to each other. These subclasses of the new compounds are characterized respectively by the following general formulae:

wherein X represents an oxygen or a sulfur atom, R represents a monovalent organic radical which is linked to the benzene ring by a carbon atom, R represents a hydrogen atom or a monovalent organic radical which is linked to the benzene ring by a carbon atom, and any pair of -Rs or of an R with R represents a divalent organic radical in which the free valence bonds are located on different carbon atoms. The benzene ring of these new compounds can thus be a part of a fused ring system which can be made up of more than one aromatic ring, or of fused aromatic and alicyclic rings. In any case it is preferred that the organic radicals represented by R and/ or by R be hydrocarbon radicals.

radicals include such straight chain alkyl radicals as the methyl, ethyl, butyl, amyl, octyl, lauryl and stearyl raddicals; such branched chain alkyl radicals as the isopropyl, secondary-, tertiaryand iso-butyl, 2-ethyl hexyl, and tetramethyl octyl radicals; cycloalkyl radicals such as cyclopentyl, cyclohexyl, Z-methylcyclopentyl and l-ethylcyclohexyl radicals; aryl radicals such as phenyl, 4-methylphenyl, 3-isopropylphenyl and naphthyl radicals; and aralkyl radicals such as the benzyl, ci-nnamyl, phenylethyl and 'naphthylmethyl radicals.

, Included among the preferred divalent hydrocarbon radicals are alkylene radicals such as the trimethylene, tetramethylene and alpha-methyltetramethylene radicals, unsaturated aliphatic radicals such as allylene (-CH:OH=OH), -OH=OH-OH=OH and -O=OHOHI- Ha radicals, and such aromatic radicals as the biphenylene radical, and the like.

The tetraalkyl-substituted benzene dissocyanates and diisothiocyanates having the functional groups in meta or para position form an especially preferred subgroup of this subclass of the compounds of the invention. This subgroup of compounds has the double advantage of not only sharing the unexpected desirable properties which characterize the class of new compounds as a whole but also of being readily synthesized in high yields as pure or substantially pure products uncontaminated by undesirable isomers. Among the simpler members of this subgroup are, for example,

Isodurene diisocyanate CH3 OH;

o=o=N Isodurene diisothiocyanate CH; CH;

s =C=N H; Isothiocyanoisodureneisocyanate (13H: 3

H3 N=O= s Durene diisocyanate CH CH OH; H;

Durene dithioisocyanate on; CH;

CH, CH;

Isothiocyanodureneisocyanate CH CH Exemplary of the corresponding higher alkyl compounds of the invention are, for instance: 1,2,3-trirnethyl- 5-ethyl-4,6-diisocyanobenzene; 1,3 dirnethyl 2,5-diethy1- 4,6-diisothiocyanobenzene; 1 methyl-2-ethyl-3,S-diisopropyl-4,6-diisocyanobenzene; 2,6 dimethyl 3,5 ditertiarybutyl-l,4-diisocyanobenzene; 2,5 diethyl 3,6-diisopropyl- 1,4-diisothiocyanobenzene; 2-methyl-3-ethyl-5-isobutyl-6- hexyl-l,4-diisocyanobenzene; and 2,3,5-trimethyl-6-decyl- 1-isocyano-4-isothiocyanobenzene.

With all the new compounds having the two groups in parapositions on the same benzene ring, it is necessary that the remaining four positions be occupied. When the -N=C:X groups are in meta position to each other, only the three positions need be occupied. Typical of the new compounds of this subgroup are the following:

1 ,3, S-trim ethyl-2,4-diisocyanob enzene N= C=O OH; -OH;

and their higher alkyl isomers such as 1-decyl-3,5-diethyl- 2,4-diisocyanobenzene; 1 isopropyl-3-methyl-5-ethyl-2,4- diisocyanobenzene; 1 allyl 3,S-dimethyl-2,4-diisocyanobenzene; l-amyl-S- (2-ethylhexy1) -5-methyl-2,4-diisothiocyanobenzene; and the like.

The following compounds are exemplary of the new diisocyanates and diisothiocyanates which have these func- 5 tional groups linked to dilferent aromatic rings in the molecule:

3,5,3 ',5 '-tetramethyl-4,4'-diisocyanobiphenyl CH; CH;

OCN -NCO CH3 H:

2,4,4,6-tetramethyl-3,5-diisocyanodiphenylmethane 0 CN CH3 H NCO As previously pointed out, the invention also includes those aromatic diisocyanates and/or diisothiocyanates which have these functional groups attached to adjacent carbon atoms on the aromatic nucleus and having both positions ortho to these functional groups occupied, preferably by hydrocarbyl groups. Representative examples of the new compounds of this type are the preferred tetraalkyl benzene compounds, of which the following are exemplary:

Prehnitene diisocyanate OH N=O=0 I CH3 Prehnitene diisothiocyanate Isothiocyanoprehniteneisocyanate and the corresponding higher compounds such as 1,2,3- triethyl-4-secondary-butyl-S,6-diisocyanobenzene; l-methyl-2,3-dipropyl-4-dodecyl-5,6-diisothiocyanobenzene; and 1,4 ditertiary amyl 2,3 dimethyl 5 isothiocyanofi-isocyanobenzene. These tetraalkyl compounds have the advantage over certain other members of this subclass of the new compounds that they can be synthesized in high yields and can be recovered easily in a form uncontaminated with undesirable materials. However, compounds of this subclass containing fewer alkyl substituents on the benzene ring are also very useful products of the invention. These include, for example, 1,4-dimethyl-2,3-diisocyanobenzene; 1,4,5-trimethyl-2,3-diisothiocyanobenzene; 1 ethyl 4 isopropyl 2 isothiocyano 3 isocyanobenzene; 1 tertiary-butyl-4,6-dimethyl-2,3-diisocyanobenzone; and 1-methyl-4-ethyl-2,3-diisothiocyanobenzene.

Among the polynuclear compounds of the invention in which the N=O=X groups are in ortho positions to each other, the following are exemplary:

1,5-dimethyl-3,4-diisocyanodiphenyl CH3 ITTOO z 4,7-dimethyl-5,6-diisocyanoindene The new compounds of the invention can be produced in various ways. One suitable method utilizes as starting materials the corresponding aromatic primary diamines having the ring carbon atoms ortho to the amino groups occupied, preferably by hydrocarbon groups, which are readily available or can be produced by known methods. For the production of the diisocyanates, the starting primary diamine or its hydrohalide salt is reacted with phosgene. US. Patents 2,680,127-130, for example, describe in detail suitable methods for carrying out this reaction. when the diisothiocyanates are the desired product, one can carry out the reaction in an analogous manner using thiophosgene instead of phosgene for reaction with the chosen aromatic primary diamine. The new diisothiocyanates can also be produced successfully by reacting the corresponding aromatic amines with carbon bisulfide, ammonium hydroxide and lead nitrate. Also, aryl thioureas decompose thermally in a solvent to give aryl isothiocyanates and ammonia. The mixed isocyano-isothiocyano compounds are readily obtained by heating the corresponding diisothiocyanates with mercurons oxide, preferably using not more than one mole of the oxide per mole of the diisothiocyanate so as to convert one of the isothiocyanate groups to an isocyanate group without converting the other isothiocyanate group.

NCO

NCO

The products of this reaction are mixtures of diisocyanate, diisothiocyanate and mixed isocyanate-isothiocyanate. These compounds can be separated by distillation, or can usually be used successfully without separation.

The following examples illustrate the production of new compounds of the invention by the foregoing methods, but it will be understood that other methods can be used.

Example I Durene diisocyanate was prepared by dissolving durenediamine in anhydrous chlorobenzene in a stirred reactor provided with a reflux condenser and heating coil, adding anhydrous hydrogen chloride to convert the diamine to the dihydrochloride, and heating the resulting suspension at 110 C. with vigorous stirring while feeding in phosgene in excess over a period of 2.5 hours. The mixture was then refluxed at 132 C. for half an hour to drive off hydrogen chloride from the carbamyl chloride. The first crop of white crystals was 57% of the theoretical amount of durene diisocyanate and melted at 113.5 1l4 C. Vacuum evaporation of the mother liquor gave a light tan solid (43% of the theoretical yield) melting at 112 C. which was recrystallized from Skelly Solv-B as white crystals melting at 113.5 114 C. for a 94% total yield of durenediisocyanate based upon the durene diamine employed.

Example I] Durene diisothiocyanate is produced by reaction as in Example I using thiophosgene instead of phosgene.

Example I11 Prehnitene diisocyanate is produced by reacting prehnitene diamine dihydrochloride with phosgene under the conditions of Example 1.

Example IV Isodurene diisocyanate is produced, by reacting under the conditions of Example I, isodurene diamine dihydrochloride with phosgene.

Example V Mesitylene diisocyanate is produced by reacting mesitylene diamine dihydrochloride with phosgene in chlorobenzene solution at 110-130 C. and recovering the crystalline product as in Example 1.

Example VI Mesitylene diisothiocyanate is produced by reacting mesitylene diamine dihydrochloride with thiophosgene under the conditions of Example V.

Example VII 1,4dimethyl-2,3-diisocyanobenzene is produced by reacting a solution of 1,4-dimethyl-2,3-diaminobenzene in chlorobenzene with anhydrous hydrogen chloride to form the dihydrochloride and running in phosgene in excess at about C. over a period of about two hours, followed by refluxing for 30 minutes. The product can be recovered as in Example I.

Example VIII 1,2-diisocyano 3 methyl-5,6,7,S-tetrahydronaphthalene is produced by reacting 1,2-diamino-3-methyl-5,6,7,- 8-tetrahydronaphthalene dihydrochloride with phosgene and refluxing as in Example I.

Example IX 1,4-dimethyl-2,3-diisocyanonaphthalene is produced by reacting 1,4-dimethyl-2,3-diaminonaphthalene dihydrochloride with phosgene under the conditions of Example I.

Example X 3,5,3',5 tetramethyl-4,4-diisocyanodiphenyl is produced by reacting 3,5,3',5'-tetramethyl-4,4'diaminodi phenyl dihydrochloride with phosgene under the conditions of Example I.

Example XI Bis-(2-isocyano-3-methylphenyl)methane is produced by reacting bis-(Z-amino-S-methylphenyl)methane dihydrochloride with phosgene under the conditions of EX- arnple I.

The new compounds are valuable intermediates in the production of other useful compounds. By reaction with hydroxy compounds they form useful carbamates, for example. Thus, warming the durene diisocyanate of Example I with excess ethyl alcohol gave the solid durene urethane CH3 CH3 O CH3 CH3 melting point 274 C. Corresponding products from isopropyl, allyl, tertiary butyl and decyl alcohols are also useful new compounds. In general, the mono and dicarbarnates of the new diisocyanatcs and diisothiocyanates with monohydric alcohols, preferably aliphatic alcohols, of l to 12 carbon atoms per molecule are valuable products of the invention.

Especially important new compositions of the invention are the polymers which are obtainable from the new diisocyanatcs and diisothiocyanates, particularly the polyurethanes which can be produced by reaction with polyols. Polyurethanes having desirable properties can, for example, be obtained by warming the new diisocyanates and diisothiocyanates with ethylene glycol. propylene glycol, trimethylene glycol, and the like. For instance, durene diisocyanate warmed with the stoichiometric amount of 1,4-butanediol gives a high melting polymer, while similar reaction with 1,5-pentanediol gives a lower melting polymer. Polymers of more advantageous prop erties are produced by similarly reacting dihydric alcohols having the carbinol groups separated by at least 4 carbon atoms, more preferably 6 to 22 carbon atoms. Typical examples of diols of this type which form valuable polymers with the new diisocyanatcs and diisothiocyanates are l,8-octanediol, 1,10-decanediol, 1,16-hexadecanediol and 1,20-eicosanediol. In preparing polymers of this kind one can use mole ratios of the new ortho hydrocarbylsubstituted diisocyanatcs and diisothiocyanates to diol of 0.7:1 to 13:1 and obtain useful linear products, but we prefer to use these compounds in about chemical equivalent proportions or a small excess up to about mole percent or diol.

Another useful type of polyol which can be employed in producing polymers with the new compounds of the invention are the polyhydroxy ethers, particularly the polyalkylene glycols such, for instance, as the polyethylene glycols having 2 to or more ethylene groups per molecule, the related polypropylene, polybutylene and like glycols.

Especially advantageous polymeric products are obtained by reacting the new aromatic diisocyanates and diisothiocyanates with polyesters having at least two hydroxy groups in the molecule. One or more of these hydroxy groups can be carboxyl hydroxy groups, but more preferably at least one, and most preferably at least two are carbinol hydroxy groups. These polyesters can be produced by known methods. They are prepared, for example, by heating one or more dibasic carboxylic acids with a glycol or mixture of glycols. Ordinarily no catalyst is necessary but the condensation can be accelerated by using p-toluenesulfonic acid, zinc or stannic chloride, hydrochloric acid, calcium acetate or the like. These catalysts are usually employed in amounts of the order of about 0.1% to 5% by weight of the reactants. The proportion of dibasic acid to glycol can be varied widely. Generally, the acids are reacted with about equimolar amounts to 50% excess of glycol, but excess dibasic acid can also be used in the reaction. It is preferred as a rule touse molar ratios of acid to glycol within the range of 1:13 to l.l:l. In most cases temperatures in the range of about 100 C. to 300 C. are satisfactory and, most preferably, the water formed in the reaction is removed as fast as it is produced.

Any dibasic carboxylic acid can be used in preparing the polyesters which are reacted with the new diisocyanates or diisothiocyanates of the invention. Representa- 8 tive examples are succinic, adipic, glutaric, sebacic, tartaric, terephthalic, beta-methyladipic, octadecylsuccinic, 1,20-eicosanedioic and like acids. Preferably saturated dicarboxylic acids having the carboxyl groups attached to terminal carbon atoms are used. Any of the previously mentioned glycols can be used for condensation with these dibasic acids in making polyesters reactive with the new compounds. Ethylene glycol, propylene glycol, diand tri-ethylene glycols, pentamethylene glycol, dodecamethylene glycol, glycerine beta-monomethyl ether, thiodiglycol, glycol monoacetate, are typical of the dihydroxy compounds which can be successfully used. It is often advantageous to employ a mixture of diols in preparing the polyesters. For instance, 75 mole percent ethylene glycol and 25 mole percent propylene gylcol in about 20% excess condensed with adipic acid, or mole percent ethylene glycol and 20 mole percent of hexamethylene glycol with mole percent of sebacic acid, give polyesters which are useful for reaction with the substituted aromatic diisocyanatcs and diisothiocyanates of the invention. In general, we prefer to use dicarboxylic acids and glycols which contain not more than 20 carbon atoms per molecule; most preferably, acids of 6 to 12 carbon atoms are used with glycols having 2 to 8 carbon atoms per molecule.

Instead of the foregoing polyesters, polyester amides such as are formed by condensing the foregoing dibasic carboxylic acids with a mixture of one or more glycols and an amino alcohol or diamine, or both, are useful in forming polymeric products with the new substituted aromatic diisocyanatcs and diisothiocyanates. Suitable amino alcohols are the primary and secondary aminosubstituted alcohols, for example, ethanolamine, 3-aminopropanol, S-amino-pentanol, 8-amino-octanol, IO-aminodecanol, lZ-amino-dodecanol, N-ethyl-ethanolamine, etc. Representative of the diamines are, for instance, ethylene diamine, tetramethylene diamine, hexamcthylene diamine, 1,6-diamino-nonane, 2,l0-diamino-dodecane, ethyl aminopropylamine, 2,2'-diaminoethyl ether, piperazine and the like. These polyesteramides can be prepared by reaction, without need for acid catalysts, under the same conditions as are used in producing the previously described polyesters. Preferably not more than one-third of the reactive hydroxyl and amino groups in the mixture condensed with the dicarboxylic acid are amino groups and, more preferably, only about 5% to 15% of such groups are amino groups.

The reaction of the polyols and polyesteramides of the types described with the substituted aromatic diisocyanatcs and diisothiocyanates, having all positions ortho to the isocyano and isothiocyano groups occupied, can be carried out in a variety of ways. Ordinarily the reaction is quite rapid at relatively low temperatures, simple Warming of the reactants being sufficient to bring about substantial reaction in most cases. In general, temperatures of about 40 to 250 C. can be used, but it is preferred to employ temperatures below about 100 C. The reaction is carried out in the liquid phase with or without solvents or diluents. The preferred solvents or diluents are inert liquids at the chosen operating temperature and pressure. Reaction times of the order of 2 or 3 minutes or less up to an hour or more can be used. It is often advantageous to carry out the reaction under a blanket of inert gas such as nitrogen, carbon dioxide, ethane, etc. Atmospheric, superatmospheric or subatmospheric pressure can be used.

The proportions in which the new diisocyanatcs and diisothiocyanates are employed relative to the polyol or polyols can be varied widely. Chemical equivalent amounts are often advantageous but an excess of either reactant in amounts as high as 100% has been found satisfactory depending upon the nature of the polymer which is desired. Higher proportions of diisecyanate or diisothiocyanate or of polyol can be used. Depending upon the proportions used, new polymers can be produced which are hard infusible resinous materials, tough leathery products, fiber-forming compositions, elastic rubbery materials, and soft waxes or viscous liquids.

The following examples show in more detail how the new polymer products can be prepared, although it will be understood that other methods of producing these polymers can also be used.

Example XII Durene diisocyanate, 40 parts, and 1,4-butanediol, 17 parts by weight, were stirred and heated on a boiling water bath for about one-half hour. The mass increased in viscosity and finally a tough solid polymer remained. The polymer did not melt at 274 C.

Example XIII By the method of Example XII, durene diisothiocyanate prepared by the method of Example II is reacted with an equal molecular amount of 1,10-decanediol. When recovered in the same way, the polyurethane polymer is much softer and more flexible than the polymer of Example XII.

Example XIV Illustrative of the production of durene diisocyanatemodified polyesters is the reaction of 0.95 mole of durene diisocyanate per mole of the polyester produced by condensing a mixture of 60% ethylene glycol and 40% propylene glycol with adipic acid using a 20% mole excess of total glycol by melting the waxy polyester with the durene diisocyanate at about 125 C. After thorough mixing, the product was heated for hours at 145 C. to obtain a rubbery polymer.

In the same way excellent products are obtained by substituting isodurene diisocyanate or prehnitene diisocyanate for the durene diisocyanate. Due to the presence of substituent groups on the ring carbon atoms ortho to the isocyano groups, the NH groups in all these urethanes are less subject to attack by isocyanates than is the case when the diisocyanates hitherto available are used in the polymers. As a result, the present products afford a more stable pot-life for the polymer intermediates and give polymers of especially useful characteristics. For use in the preparation of polymeric materials, the diisocyano compounds of the invention having the isocyano groups in para position on a benzene ring are preferred. Durene diisocyanate is a most advantageous compound of this type.

The new polymers can be used alone or with other polymers with or without other materials such as plasticizers, softeners, pigments, stabilizers, solvents, etc.

While the use of the new diisocyanates and diisothiocyanates in the manufacture of polymeric products has been emphasized because of their great advantage over prior compounds in this field, these new products have other advantageous uses. They are especially valuable agricultural chemicals, durene diisocyanate and durene diisothiocyanate being particularly useful in this respect. The invention is not limited to the examples which have been given by way of illustration nor by any theory proposed in explanation of the improved results which are obtained. The new diisocyanates and diisothiocyanates of the invention are claimed in a eopending application of applicants.

We claim as our invention:

1. A polymeric product of reaction of 1) a member of the group consisting of benzene, biphenyl, and diphenylmethane substituted by two radicals of the group consisting of isocyanato and isothiocyanato in which the positions ortho to each of said two radicals are each substituted by an alkyl radical, with (2) a polyhydroxy compound of the group consisting of polyhydroxy alkanes, hydroxy terminated ethers, and hydroxy terminated esters.

2. A polyurethane. reaction product of a polyalkylbenzene diisocyanate having an alkyl group attached to each of the ring carbon atoms in a position ortho to each of the isocyanato groups, and a saturated aliphatic glycol having 2 to 10 carbon atoms per molecule.

3. A polymeric product of reaction of a tetraalkylbenzene diisocyanate having 1 to 18 carbon atoms in each of the alkyl groups and wherein an alkyl group is attached to each of the ring carbon atoms in a position ortho to each of the isocyanato groups and a substantially hydroxy terminated polyester of at least one dicarboxylic acid and a glycol.

4. A polymeric reaction product of a tetraallcylbenzene diisocyanate having 1 to 18 carbon atoms in each of the alkyl groups and wherein an alkyl group is attached to each of the ring carbon atoms in a position ortho to each of the isocyanato groups and a polyhydroxy alkane.

5. A polymeric reaction product of a tetraalkylbenzene diisocyanate having 1 to 18 carbon atoms in each of the alkyl groups and wherein an .alkyl group is attached to each of the ring carbon atoms in .a position ortho to each of the isocyanato groups and a hydroxy terminated ether having at least two hydroxyl groups.

6. A polymeric reaction product of durene diisocyanate and a substantially hydroxy terminated polyester of at least one dicarboxylic acid and a glycol.

7. A polymeric reaction product of durene diisocyanate and .a hydroxy terminated ether having at least 2 hydroxyl groups.

8. A polymeric reaction product of durene diisocyanate and a hydroxy terminated polyalkylene-ether glycol.

9. A polymeric reaction product of a polyalkyldiphenylmethane diisocyanate having a methyl group attached to each of the ring carbon atoms in a position ortho to the isocyanato groups, and a polyhydroxy compound of the group consisting of polyhydroxy alkanes, hydroxy terminated ethers, and hydroxy terminated esters.

10. A polyurethane of durene diisocyanate and an alpha,omega-alkylene diol having 4 to 6 carbon atoms per molecule.

11. The process of preparing a polyurethane reaction product which comprises reacting (1) a polyhydroxy compound selected from the group consisting of polyhydroxy alkanes, polyalkylene ether glycols and hydroxyl terminated polyesters which are the reaction product of a polycarboxylic acid and a polyhydric alcohol with (2) a tetramethyl benzene diisocyanate, said diisocyanate having the isocyanate groups in non-adjacent positions.

References Cited in the file of this patent UNITED STATES PATENTS Copy in Sci. Libr.

Siefkin: Annalen der Chemie, vol. 562, 1949, p. 127. Siefkin: Annalen der Chemie, vol. 562, 1949, pp. 121- 136. Copy in Scientific Library. 

1. A POLYMERIC PRODUCT OF REACTION OF (1) A MEMBER OF THE GROUP CONSISTING OF BENZENE, BIPHENYL, AND DIPHENYLMETHANE SUBSTITUTED BY TWO RADICALS OF THE GROUP CONSISTING OF ISOCYANATO AND ISOTHIOCYANATO IN WHICH THE POSITIONS ORTHO TO EACH OF SAID TWO RADICALS ARE EACH SUBSTITUTED BY AN ALKYL RADICAL, WITH (2) A POLYHYDROXY COMPOUND OF THE GROUP CONSISTING OF POLYHYDROXY ALKANES HYDROXY TERMINATED ETHERS, AND HYDROXY TERMINATED ESTERS. 